Whew I am late to the party. I too have read through this entire thread as well as lots of other pieces of information on the web.
Piyoman your
Instructables post and Dave Arnold's
walk through (both mentioned previously in this thread) have been my bible. Although Piyo, I've never quite understood why you went ~45psi and then watered it down. Everything I've read is double that unless going for more of a subtle sparkle like Perrier? Tyler, thanks for posting on this and bringing it back. I saw your video previously after I had put most of my system together. I registered just to post here hoping some of the other guys are still around to comment.
Seltzer and all of its knowhow and specific parts (high pressure, barrier/bev-line tubing, flare fittings, stainless everything not chrome or bare brass, 1/4" ID not 3/16" or other, flow control compensators not pooled smaller line in your fridge for resistance, on and on and on) are like searching for a needle in a haystack amongst everything beer. Exhausting.
I have have now spent 4 weeks putting this together and am very, very close after much final reconfiguring. I decided to keep everything cold together in a 4.4cu ft mini fridge, but with the pump on the outside. I have been doing lots of back and forth with beer parts and brewers advice for weeks now as alluded to, including working with items like beer towers with Perlick 650ss or the new Nukatap flow control faucets (which now have their own special shanks), to play nicely with everything seltzer.
Somehow this week I stumbled upon an incredibly good deal for an IBIS dual draft seltzer tower complete with the proper CM Becker flow control compensator faucets and it was like a gift from the universe. Seriously. When this IBIS arrives, I will finally have this station complete and can return all the other beer-aphernalia. Lots of build photos if any are interested. After many hours and weeks in the making I am excited to finally be pouring! Cheers, Will